Improvement in bit-brace



'y A, and rose, F, in the usualfmanner.

, and 5.

en-iai sang @wat @titre 'SnnPAnnson or SHELBURNE FALLS, MASSACHUSETTS.

Letters Patent N 100,458, dated Merch l, 1870.

. nvi'PRovnMBNT 1N BIT-Bruton The Schedule referred to in these Letters Patent-and making part of the same.

all 'whom 'it 'may concern v Be it known tha-t1, H. S. SI-IEPARDSON, of Shel- -burne iFalls, iu thecountyof Franklin, and State of` Massachusetts, have `invented certain improvements in Bit-Stocks, ofl which the vi'ollo\\ rii 1g.is a speciiication,

re .rence being had tothe accompanying drawings.

M y invention'relates to bit-stocks; and

. The invention consists ina nevel construction of the parts which secure the bit inthe stock, as hereinafter more fully explained,

`Figurel is a side elevation-ofmy improved bitstoek complete; j j j Figureis a vscct'imifo'n the line t :t of iig. 3, with one jaw removed;

. Figure 3 is an end View', Figure 4, ,a cro'ss-sectol'i of the jaws o nthe line 1/ and Figure V5 is a sectional view on the line x a: of iig. 3 with a bit inserted. i 1n constructing-luy-iinproved stock, I make the body Upon the opposite orjlower end I secure a head, B,

v soun-what larger `in, diameterthanthe body, and-in thishead `lorln longitudinally a conical'A socket, f, as shown in figs. 2 and 5.

"The exterior of this headB, at itsend, is also made l. eonieal, with a flange or collar at its extreme end, and has iitied upon it a ring or loose collar, D, which has a serew-threzui cnt on its interior, as shown in iigs. 2

1u `opposite sides ofthe head B, I cut grooves e, as seats for the sliding jaws C. These grooves are formed in the arc oi' a circle longitudinally, andare rectangula-r transversely, the jaws being made ot' a correspending l'orln, as shown in figs. 2 and 5, and having teeth or sectional sere\\'tln'ezuls on their exterior t'aee, to engage with the sere\\'tlil ead on the interior ofthe ring l). 4 These jaws also have a V-shaped recess or -r:|-vit \;1n:nle longitudhmlly intheir inner faces, as represented n vigs. 2, 3, and4. This cavity doesnote'xtend the entire 'length ofthe jaws C, but commences gradually near one end, and increases iu depth until 4 near the opposite end, where they cease entirely, as

. The parts being thus constructed, the ring D is slipped down to its position against the flange on the end of the head B, whcreit is secured by a small collar,

o, screwed on above it, as shown in iiff. 1, or by apin,

as may be preferred'. The jaws C being Vthen inserted from the outer end into the grooves e, the ring D is turned, which draws the jaws inward, as shown in fig. A small pin, c, is then inserted in a hoiencar the inner end of one ofthe jaws, as shown in fig.5, which pin serves as 4a stop when it strikes against the edge ofthe ring D, las represented in tig. 2,.thereby preventing the jaws fromvbeing 'screwed out beyond a certain point. Y

'In operation, a bit, E, is inserted into the .conical cavity in the end ofthe head B, and the ring D is then turned in the propel' direction to draw the jaws C inwardfrom the end. l

In consequence of the segmental or curved form of the jaws, and of the grooves ill which they slide, their outer ends are. drawn towards each other as they recede, thns clasping thel shank of the bit E between them,.the.outer ends ofthe jaws grasping over the shoulders of the bit-shanlgthereby-iorcing the b it v firmly down into the socket of 'the head B, and holdilar tool-holding device, substantially as described. i

2. A bit-stock having the curvedjaws C, ringD, andV head B, constructed and arranged' to operate suhstantially as set forth.

' H. S. SHEPARDSON. `Witnesseszy H. Muss, 

